Solar Loan Payment Calculator
A solar loan's advertised monthly payment can hide just how much interest you're actually paying over the full term. This calculates both directly from your principal, APR, and term.
At your inputs, the monthly payment is $144, with a total finance charge of $9,886 over the loan term.
| Monthly payment | $144 |
|---|---|
| Total loan cost (principal + interest) | $25,886 |
| Total finance charge (interest only) | $9,886 |
- This uses planning estimates you entered, not a lender's actual offer.
- A lower monthly payment from a longer term increases the total finance charge; weigh both together.
What this also tells you: The finance charge of $9,886 is the true cost of financing instead of paying cash; compare it directly against any cash-vs-loan tool before deciding.
This is a planning estimate based on your entries. It does not size equipment, determine electrical or building-code compliance, verify incentive eligibility, or replace a contractor quote or professional energy audit.
Why this decision comes up
A homeowner financing solar is often shown only a monthly payment figure, without a clear view of the total interest cost that payment implies over the full loan term.
How this is calculated
Your principal, APR, and term are run through a standard amortization calculation to produce a monthly payment, a total loan cost, and the finance charge, the interest portion, on its own.
A worked example
With the defaults ($16,000 principal, 7% APR, 15-year term), the monthly payment comes out to $143.81, with a total loan cost of $25,886.25 over the full term, meaning a finance charge of $9,886.25 in interest alone, more than half the original principal.
Common mistakes
A common mistake is focusing only on the monthly payment without checking the total finance charge, which is the real cost of choosing to finance instead of paying cash.
Limitations
This uses the loan terms you enter, not a specific lender's actual offer. Confirm your real APR and any fees with your lender before relying on this figure.
Common questions
What should I use as the principal?
The amount you actually need to finance: the system cost minus any down payment and minus any confirmed incentive you are applying at closing rather than claiming later on your taxes.
Why does a longer term lower the payment but raise the total cost?
Spreading the same principal over more months lowers each individual payment, but you pay interest for a longer stretch of time, which raises the total finance charge overall.
How do I compare this against paying cash?
Use the finance charge shown here as your financed annual cost input, then run the cash vs. loan tool for a direct total-cost comparison.
Does this include any loan origination fees?
No, enter your true financed principal already reflecting any fees rolled into the loan, or add the fee separately to your total cost comparison elsewhere.
Can I use this for a home equity loan instead of a dedicated solar loan?
Yes, the amortization math is the same regardless of loan type. Use your home equity loan's actual principal, rate, and term.